docs: add js release notes for 1.20 (#12575)

docs/src/release-notes-js.md

@@ -5,6 +5,90 @@ title: "Release notes"
 
 <!-- TOC -->
 
+## Version 1.20
+
+### Visual Regression Testing
+
+- New options for methods [`method: Page.screenshot`], [`method: Locator.screenshot`] and [`method: ElementHandle.screenshot`]:
+  * Option `animations: "disabled"` rewinds all CSS animations and transitions to a consistent state
+  * Option `mask: Locator[]` masks given elements, overlaying them with pink `#FF00FF` boxes.
+- New web-first assertions for screenshots: [`method: PageAssertions.toHaveScreenshot`] and [`method: LocatorAssertions.toHaveScreenshot`]. These methods will re-take screenshot until it matches the saved expectation. When generating a new expectation, the method will re-take screenshots until 2 consecutive screenshots match.
+
+  New methods support both named and anonymous (auto-named) expectations:
+
+  ```js
+  // Take a full-page screenshot with a named expectation `fullpage.png`.
+  await expect(page).toHaveScreenshot('fullpage.png', { fullPage: true });
+  // Take a screenshot of an element with anonymous expectation.
+  await expect(page.locator('text=Booking')).toHaveScreenshot();
+  ```
+
+  Methods support all screenshot options from [`method: Page.screenshot`] and [`method: Locator.screenshot`].
+
+  These methods also support new `maxDiffPixels` and `maxDiffPixelRatio` options for fine-grained screenshot comparison:
+
+  ```js
+  await expect(page).toHaveScreenshot({
+    fullPage: true, // take a full page screenshot
+    maxDiffPixels: 27, // allow no more than 27 different pixels.
+  });
+  ```
+
+  It is most convenient to specify `maxDiffPixels` or `maxDiffPixelRatio` once in [`property: TestConfig.expect`].
+
+### Other Updates
+
+- Playwright Test now adds [`property: TestConfig.fullyParallel`] mode. By default, Playwright Test parallelizes between files. In fully parallel mode, tests inside a single file are also run in parallel. You can also use `--fully-parallel` command line flag.
+
+  ```ts
+  // playwright.config.ts
+  export default {
+    fullyParallel: true,
+  };
+  ```
+
+- [`property: TestProject.grep`] and [`property: TestProject.grepInvert`] are now configurable per project. For example, you can now
+  configure smoke tests project using `grep`:
+  ```ts
+  // playwright.config.ts
+  export default {
+    projects: [
+      {
+        name: 'smoke tests',
+        grep: '@smoke',
+      },
+    ],
+  };
+  ```
+
+- [Trace Viewer](./trace-viewer) now shows [API testing requests](./src/test-api-testing).
+- `expect().toMatchSnapshot()` now supports anonymous snapshots: when snapshot name is missing, Playwright Test will generate one
+  automatically:
+
+  ```js
+  expect('Web is Awesome <3').toMatchSnapshot();
+  ```
+
+- [`method: Locator.highlight`] visually reveals element(s) for easier debugging.
+
+### Announcements
+
+- We now ship a designated Python docker image `mcr.microsoft.com/playwright/python`. Please switch over to it if you use
+  Python. This is the last release that includes Python inside our javascript `mcr.microsoft.com/playwright` docker image.
+- v1.20 is the last release that ships WebKit for macOS 10.15 Catalina. All future versions will support WebKit for macOS 11 BigSur
+  and up.
+
+### Browser Versions
+
+- Chromium 101.0.4921.0
+- Mozilla Firefox 97.0.1
+- WebKit 15.4
+
+This version was also tested against the following stable channels:
+
+- Google Chrome 99
+- Microsoft Edge 99
+
 ## Version 1.19
 
 ### Playwright Test Update